Research Of Homogenization Heat Treatment And TIG Surface Remelting Of6061Aluminum Alloy

6061aluminum alloy is an Al-Mg-Si three series aluminum alloy, which has moderateintensity and suitable machining properties, can offer wide range of application. But sincethe casting-state structure of6061aluminum alloy have composition segregation and otherorganizational defects usually, and the protection from its own aluminum oxide film islimited. thus the machining comes to be more difficult and the level of quality of theproducts would be reduced. Focusing on different parts of casting-state6061aluminumalloys have different annealing laws and the trace elements impact on the organizationtransformation of homogenization, the experimental results could be important reference toactual industrial productionUnder the conditions of560℃, Researching found the general trend of the two alloysannealing process is that, With the extension of the holding time, the alloying elementsspread gradually, the crystal boundary segregation disappear slowly, the distribution ofalloying elements becomes uniform, only part of the insoluble compounds exists. Theannealing speed of different alloy parts is significantly different. It is found that theannealing speed of epidermal structure is significantly faster than the middle and the corestructure. And the annealing speed of the two different alloys has difference also. especiallythe middle and core structure.Based on the analysis the trace elements effects on homogenization, the research foundthat under the conditions of560℃,annealing effect of the Cu and Zn is poor,and thetransition of iron-rich phases from β-AlFeSi phase to α-AlFeSi phase depends on theparticipation of Mn element. The content of Mn has a significant impact on the speed ofchange of iron-rich phase. Under these conditions, the redissolution speed of Mg2Si alloy isfastest, followed by iron-rich phase and others. In addition, the effect of different coolingrate on the homogenization annealing treatment is mainly reflected in the amount of precipitation and the size of Mg2Si in the annealed structures. And this impact on theiron-rich phases is not obvious.The common argon arc welding machine is used as source of heat to achieve the surfaceremelting. the experimental results show that surface remelting treatment has a big impact onboth the microstructure and mechanical properties of the6061aluminum alloy. especially theiron-rich phases. the homogenization degree of iron-rich phases is superior to ordinaryannealing process under this experimental condition. After remelting, the enhancement ofthe average surface micro-hardness can be more than10percent. And with the increase ofremelting current, the coefficient of friction increases, at the same time the abrasion loss ofalloy has been greatly reduced and gradually stabilized. In addition, the corrosion behaviorsof6061aluminum alloy in5percnt NaCl solution show that surface remelting treatment canbe very helpful. The lost of corrosion is reducing, and corrosion way translate fromintergranular to pitting corrosion corrosion after surface remelting.